DOCSLIB.ORG

THE BIODIVERSITY CRISIS: WHY POPULATION MATTERS a Population Matters Briefing EXECUTIVE SUMMARY

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
THE BIODIVERSITY CRISIS: WHY POPULATION MATTERS a Population Matters Briefing EXECUTIVE SUMMARY THE BIODIVERSITY CRISIS: WHY POPULATION MATTERS A Population Matters Briefing EXECUTIVE SUMMARY 1. The global human population has increased from 3.7 billion in 1970 to over 7.8 billion today. The UN projects that it will continue to increase throughout this century. Its median projection is for a population of 10.9 billion by 2100, with a 95% certainty range of 9.4-12.7 billion. 2. Biodiversity loss has been accelerating and the extinction rate is now so high that scientists have established we are in the middle of a sixth mass extinction – the Anthropocene – driven by human activity. By far the biggest culprits are habitat destruction and the overexploitation of wild species. These are joined by pollution, climate change, and invasive species and disease. Human population growth acts as a direct driver of all of these factors, except invasive species and disease, where it nevertheless can contribute due to human population movements. The failure to address population under the 2010 Aichi Biodiversity Targets, which expired in 2020, is likely to have contributed to the failure to achieve any of the twenty targets. 3. The significant contribution of population 5. The most effective solutions all directly growth to global biodiversity loss has been benefit everyone: unhindered access to directly acknowledged and addressed in a modern family planning and good quality number of key and authoritative scientific education, empowering women and girls to papers, reports and reviews in recent years. make choices about their bodies and their Many directly call for action to address future lives, as well as helping to lift families and growth. entire communities out of poverty. That long- term benefits to the Earth and its biodiversity 4. Significant results from any action intended also arise reinforces the central importance to slow global population growth will take at of redoubling efforts to achieve them. least a generation to manifest, but will have permanent and irreversibly positive effects 6. As a key driver of the main causes of throughout this century and beyond. Action biodiversity loss, human population growth to ensure future population growth does not is an appropriate and necessary issue for endanger the Earth’s biodiversity is therefore attention in the post-2020 framework of the essential now. UN Convention on Biological Diversity. 2 INTRODUCTION Ecosystems, interdependent webs of living food, water and energy, amongst many other organisms and their physical environments, are finite and renewable resources. They have vital to all life on Earth. Our ecosystems provide also contributed to the climate change that is us with a vast range of vital resources, including damaging natural habitats, changing disease clean air, fresh water, food, raw materials patterns and acidifying the oceans. Plastic and medicines. Biodiversity, the variation pollution, desertification and the eutrophication of life on Earth, is a major factor in nature’s of waterways through fertiliser use are amongst resilience. In a biodiverse ecosystem, if the multiple other problems exacerbated by environment changes and some organisms can unsustainable population growth. no longer thrive, others can take their place and fulfil essential functions. Numerous authoritative scientific papers, reports and reviews have identified human However, the biodiversity of Earth’s population growth as a driver of biodiversity ecosystems is under increasing threat from loss. While other factors also contribute and human population growth. For example, must be addressed, not least unsustainably high according to WWF’s Living Planet Report and profoundly unequal per capita 2020, “relentless human population growth consumption, addressing population must form is putting a damaging strain on the world’s a critical part of the suite of solutions. plant diversity” 1; and since 1970, populations Fortunately, the mechanisms which reduce of wild vertebrate animals have declined by fertility rates also improve human rights and 68%2 – in the same period, the global human well-being in multiple ways, and speed up population has more than doubled, increasing progress towards attainment of the Sustainable from 3.7 billion to over 7.8 billion today. These Development Goals. extra billions of people have all required land, WILD VERTEBRATE ANIMAL POPULATIONS HAVE DECLINED BY TWOTHIRDS IN THE PERIOD THE HUMAN POPULATION HAS DOUBLED +103% -68% 1970 2016 Source WWF Living Planet Report 2020/United Nations Population Division 3 POPULATION PROSPECTS According to the most recent UN projections, the global population will continue to increase throughout this century. Its median projection is for a population of 10.9 billion by 2100, with a 95% certainty range of 9.4-12.7 billion.3 It is important to remember that while population growth is highest in the Global South, and relatively low in most parts of the Global North, consumption, resource use and carbon emissions are far greater in the richest parts of the world. This means that the global environmental impact on nature and biodiversity of each individual in wealthy countries is far higher than that of each individual in poor countries. Therefore, the size of the overall population in the Global North matters, too. UNITED NATIONS POPULATION PROJECTIONS POPULATION GROWTH BY CONTINENT, 2020-2100 16 AFRICA 14 ASIA 12 EUROPE 10 LATIN AMERICA 08 AND THE CARIBBEAN 06 NORTHERN WORLD POPULATION (BILLIONS) POPULATION WORLD AMERICA 04 OCEANIA 02 0 1,000 2,000 3,000 4,000 5,000 6,000 1950 2000 2050 2100 POPULATION (MILLIONS) median projection 2020 2050 2100 Source UN, 2019 Source United Nations, 2019 4 HUMAN POPULATION GROWTH AND BIODIVERSITY LOSS The drivers of biodiversity loss Biodiversity loss has been accelerating and the extinction rate is now so high that scientists have established we are in the middle of a sixth mass extinction – the Anthropocene – driven by human activity.4 Biodiversity loss has several primary drivers, which are all well-recognised. By far the biggest culprits are habitat destruction and the overexploitation of wild species. These are joined by pollution, climate change, and invasive species and disease. Human population growth acts as a direct driver of all these factors, except invasive species and disease, where it nevertheless can contribute due to human population movements. The impact of population growth urgent action, the IPBES states, “changes to the at local level, particularly in regard to habitat direct drivers of nature deterioration cannot be loss and overexploitation, is widely recognised. achieved without transformative change that According to the Intergovernmental Science- simultaneously addresses the indirect drivers.”6 Policy Platform on Biodiversity and Ecosystem Services (IPBES), only one quarter of land Research published in the July 2017 areas and one third of oceans remain relatively Proceedings of the US National Academy of undamaged by human activity.5 Sciences reviewed data on 27,600 terrestrial vertebrate species, with a more detailed The population factor analysis of 177 mammal species. It identified A number of scientific papers, reports and the proximate causes of population extinctions reviews in recent years have directly addressed as “habitat conversion, climate disruption, the role of population growth in global overexploitation, toxification, species biodiversity loss. invasions, disease, and (potentially) large- scale nuclear war’’, and concluded that “the The most significant and high-profile is ultimate drivers of those immediate causes of the IPBES global assessment of the state of biotic destruction [are] human overpopulation biodiversity, published in May 2019. The and continued population growth, and report identifies direct and indirect drivers of overconsumption, especially by the rich.” 7 biodiversity loss, itemising population growth as one of the latter, alongside consumption Extracting the specific role of population in patterns, technological innovation and biodiversity loss is a complex task that was governance. In its prescription for vital and nevertheless undertaken in two papers in 2019. 5 In Nature Ecology & Evolution, Marques resource extraction. From 2000 onwards, et al examined biodiversity loss and carbon increasing affluence overtook population as the sequestration through the measures of biggest driver, except for in Africa and West bird diversity and deforestation, and used Asia, where rapid population increase remains decomposition analysis to quantify the the biggest cause.9 particular impacts of drivers including population and affluence. The research One of the scientific papers with the greatest identified that environmental impact per unit impact of recent years10 has been the World of GDP has been declining, suggesting a greater Scientists’ Warning to Humanity: A Second efficiency of environmentally relevant economic Notice, published in Bioscience in 2017. This activities. However, these efficiency gains were paper has now been endorsed by more than cancelled by overall growth, and the authors 20,000 scientists. It details decline in almost concluded that “economic and population every marker of environmental resilience, growth have been driving the upward trend and warns of “catastrophic biodiversity of impacts on biodiversity and ecosystem loss.” The paper identifies “continued rapid services, despite a reduction of the impacts population growth as a primary driver behind per unit of GDP.”8 many ecological and even societal threats.” The Warning
Load more

Recommended publications
  • Land-Use, Land-Cover Changes and Biodiversity Loss - Helena Freitas
    LAND USE, LAND COVER AND SOIL SCIENCES – Vol. I - Land-Use, Land-Cover Changes and Biodiversity Loss - Helena Freitas LAND-USE, LAND-COVER CHANGES AND BIODIVERSITY LOSS Helena Freitas University of Coimbra, Portugal Keywords: land use; habitat fragmentation; biodiversity loss Contents 1. Introduction 2. Primary Causes of Biodiversity Loss 2.1. Habitat Degradation and Destruction 2.2. Habitat Fragmentation 2.3. Global Climate Change 3. Strategies for Biodiversity Conservation 3.1. General 3.2. The European Biodiversity Conservation Strategy 4. Conclusions Glossary Bibliography Biographical Sketch Summary During Earth's history, species extinction has probably been caused by modifications of the physical environment after impacts such as meteorites or volcanic activity. On the contrary, the actual extinction of species is mainly a result of human activities, namely any form of land use that causes the conversion of vast areas to settlement, agriculture, and forestry, resulting in habitat destruction, degradation, and fragmentation, which are among the most important causes of species decline and extinction. The loss of biodiversity is unique among the major anthropogenic changes because it is irreversible. The importance of preserving biodiversity has increased in recent times. The global recognition of the alarming loss of biodiversity and the acceptance of its value resultedUNESCO in the Convention on Biologi – calEOLSS Diversity. In addition, in Europe, the challenge is also the implementation of the European strategy for biodiversity conservation and agricultural policies, though it is increasingly recognized that the strategy is limitedSAMPLE by a lack of basic ecological CHAPTERS information and indicators available to decision makers and end users. We have reached a point where we can save biodiversity only by saving the biosphere.
    [Show full text]
  • Statistical Analysis of Human Overpopulation and Its Impact on Sustainability
    Statistical Analysis of Human Overpopulation and its Impact on Sustainability Susanne Bradley Abstract In this project, I examine the relationship between population size and resource use, with particular emphasis on carbon emissions. I use a combination of time series methods and regression analysis to obtain forecasts for global carbon emissions and energy use to the year 2060, taking into account population growth and economic development. In general, my predictions are consistent with predictions already made by different experts, though mine tend to be slightly more pessimistic. I end by addressing some potential ways to decrease population growth rates. 1 Introduction In the twentieth century, human population nearly quadrupled from 1.6 billion to 6.1 billion. Over that same period of time, global carbon consumption increased by a factor of twelve [1]. Population growth has begun to slow, especially in developed countries, but global population is not expected to reach peak levels for at least thirty years [2][3]. In light of these trends, a natural question to ask is whether the Earth can support these kinds of increases in both population and per capita consumption. The population aspect of this is important because if we assume that available resources are finite, then a smaller population size may not solve the problem of overconsumption but it will slow demand for resources and give us more time to develop sustainable long-term solutions. Despite the intuitively clear relationship between population and resource consumption, the issue of overpopulation is one that has been largely ignored in scientific circles since the 1970s [4].
    [Show full text]
  • Energy Development's Impacts on the Wildlife, Landscapes, And
    Losing Ground: Energy Development’s Impacts on the Wildlife, Landscapes, and Hunting Traditions of the American West A Report by the National Wildlife Federation and the Natural Resources Defense Council Barbara Wheeler he iconic game species of the American wildlife are an ecological marker for the health of non- West are in perilous decline, as migratory game species, which are also becoming increasingly T animals lose ground to energy development vulnerable to the effects of energy development. and habitat destruction in southeast Montana and northeast Wyoming. Sage-grouse, mule deer, and Bountiful wildlife populations are a major part of the pronghorn are facing decreasing herd sizes and cultures and economies of Montana and Wyoming. downward long-term population trends, which Deteriorations in habitat quality associated with threaten the continued viability of these species in energy development can negatively affect wildlife the coming decades. Of the species considered, only populations and, in turn, impact hunters, wildlife- elk populations are forecast to rebound and stabilize watchers, and the tourism industry as a whole, which brings millions of people and billions of dollars to that additional habitat loss or degradation from the region every year. These impacts justify the need from historic lows, though there is significant concern energy development could stall population growth and for land management reforms and for wide-scale further displace the species. Simultaneously, big game investments in game and non-game wildlife protection Losing Ground Jack Dempsey at state and federal levels to offset the increasing impact on wildlife from energy development. Oregon Department of Fish and Wildlife A study commissioned by the National Wildlife Federation and the Natural Resources Defense A study commissioned by the Council analyzes trends in population and hunting National Wildlife Federation and opportunities for mule deer, pronghorn, elk, and the Natural Resources Defense greater sage-grouse.
    [Show full text]
  • World Fertility and Family Planning 2020: Highlights (ST/ESA/SER.A/440)
    World Fertility and Family Planning 2020 Highlights ST/ESA/SER.A/440 Department of Economic and Social Affairs Population Division World Fertility and Family Planning 2020 Highlights United Nations New York, 2020 The Department of Economic and Social Affairs of the United Nations Secretariat is a vital interface between global policies in the economic, social and environmental spheres and national action. The Department works in three main interlinked areas: (i) it compiles, generates and analyses a wide range of economic, social and environmental data and information on which States Members of the United Nations draw to review common problems and take stock of policy options; (ii) it facilitates the negotiations of Member States in many intergovernmental bodies on joint courses of action to address ongoing or emerging global challenges; and (iii) it advises interested Governments on the ways and means of translating policy frameworks developed in United Nations conferences and summits into programmes at the country level and, through technical assistance, helps build national capacities. The Population Division of the Department of Economic and Social Affairs provides the international community with timely and accessible population data and analysis of population trends and development outcomes for all countries and areas of the world. To this end, the Division undertakes regular studies of population size and characteristics and of all three components of population change (fertility, mortality and migration). Founded in 1946, the Population Division provides substantive support on population and development issues to the United Nations General Assembly, the Economic and Social Council and the Commission on Population and Development. It also leads or participates in various interagency coordination mechanisms of the United Nations system.
    [Show full text]
  • The Anthropocene: Acknowledging the Extent of Global Resource Overshoot , and What We Must Do About It
    Research, education, and policy guidance for a better global future. The Anthropocene: Acknowledging the extent of global resource overshoot , and what we must do about it. Research, education, and policy guidance for a better global future. Understanding the balance between human needs and environmental resources Research, education, and policy guidance for a better global future. The Anthropocene Story 3 minute video Reflections on the Anthropocene Story “ … we must find a safe operating space for humanity” “... we must understand resource limits and size ourselves to operate within planetary boundaries” Reflections on the Anthropocene Story “…our creativity, energy, and industry offer hope” Empty words Cognitive and behavioral paradigm shifts would offer ‘guarded’ optimism for the future. A preview of this afternoon’s discussion: 1. Realistic meta-level picture of humanity’s relationship with the planet 2. Talk about that relationship and the conceptual meaning of sustainability 3. Discuss the need for ‘transformative’ change and one approach to achieving future sustainability The Problem Climate change is not the problem. Water shortages, overgrazing, erosion, desertification and the rapid extinction of species are not the problem. Deforestation, Deforestation, reduced cropland productivity, Deforestation, reduced cropland productivity, and the collapse of fisheries are not the problem. Each of these crises, though alarming, is a symptom of a single, over-riding issue. Humanity is simply demanding more than the earth can provide. Climate change Witnessing dysfunctional human behavior Deforestation Desertification Collapse of fisheries Rapid extinction of species Supply = 1 Earth Today’s reality: Global Resource Overshoot How do we know we are - living beyond our resource means? - exceeding global capacity? - experiencing resource overshoot? • Millennium Ecosystem Assessment Released in 2005, the Millennium Ecosystem Assessment was a four-year global effort involving more than 1,300 experts that assessed the condition of and trends in the world’s ecosystems.
    [Show full text]
  • Intercultural Competence and Skills in the Biology Teachers Training from the Research Procedure of Ethnobiology
    Science Education International 30(4), 310-318 https://doi.org/10.33828/sei.v30.i4.8 ORIGINAL ARTICLE Intercultural Competence and Skills in the Biology Teachers Training from the Research Procedure of Ethnobiology Geilsa Costa Santos Baptista*, Geane Machado Araujo 1Department of Education, State University of Feira de Santana, Feira de Santana City, Bahia State, Brazil, 2Department of Biology, State University of Feira de Santana, Feira de Santana City, Bahia State, Brazil *Corresponding Author: [email protected] ABSTRACT We present and discuss the results of qualitative research based on a case study with biology undergraduate students from a public University of Bahia state, Brazil. The objective was to identify the influence of practical experiences involving ethnobiology applied to science teaching on intercultural dialogue into their initial training. To collect data, undergraduate students were asked to construct narratives revealing the influences of ethnobiology into their training as future teachers. Data were analyzed according to Bardin (1977) and supported by specific literature from the fields of science education and teaching. The thematic categories generated lead us to conclude that the undergraduates of biology teaching made reflections that allowed them to build opinions with meanings that should influence their pedagogical practices with intercultural dialogue. We recommend further studies involving ethnobiology and the training of biology teachers, with a larger sample of participants and the methodological and theoretical procedures of this science. Improvements could be made in biology teacher education curricula that encourage respect and consideration of cultural diversity. We highlight that it is imperative for teacher education courses to generate opportunities for on-site practical experience, in addition to the theory used in the classroom.
    [Show full text]
  • “Anthropocene” Epoch: Scientific Decision Or Political Statement?
    The “Anthropocene” epoch: Scientific decision or political statement? Stanley C. Finney*, Dept. of Geological Sciences, California Official recognition of the concept would invite State University at Long Beach, Long Beach, California 90277, cross-disciplinary science. And it would encourage a mindset USA; and Lucy E. Edwards**, U.S. Geological Survey, Reston, that will be important not only to fully understand the Virginia 20192, USA transformation now occurring but to take action to control it. … Humans may yet ensure that these early years of the ABSTRACT Anthropocene are a geological glitch and not just a prelude The proposal for the “Anthropocene” epoch as a formal unit of to a far more severe disruption. But the first step is to recognize, the geologic time scale has received extensive attention in scien- as the term Anthropocene invites us to do, that we are tific and public media. However, most articles on the in the driver’s seat. (Nature, 2011, p. 254) Anthropocene misrepresent the nature of the units of the International Chronostratigraphic Chart, which is produced by That editorial, as with most articles on the Anthropocene, did the International Commission on Stratigraphy (ICS) and serves as not consider the mission of the International Commission on the basis for the geologic time scale. The stratigraphic record of Stratigraphy (ICS), nor did it present an understanding of the the Anthropocene is minimal, especially with its recently nature of the units of the International Chronostratigraphic Chart proposed beginning in 1945; it is that of a human lifespan, and on which the units of the geologic time scale are based.
    [Show full text]
  • Golden Spikes, Transitions, Boundary Objects, and Anthropogenic Seascapes
    sustainability Article A Meaningful Anthropocene?: Golden Spikes, Transitions, Boundary Objects, and Anthropogenic Seascapes Todd J. Braje * and Matthew Lauer Department of Anthropology, San Diego State University, San Diego, CA 92182, USA; [email protected] * Correspondence: [email protected] Received: 27 June 2020; Accepted: 7 August 2020; Published: 11 August 2020 Abstract: As the number of academic manuscripts explicitly referencing the Anthropocene increases, a theme that seems to tie them all together is the general lack of continuity on how we should define the Anthropocene. In an attempt to formalize the concept, the Anthropocene Working Group (AWG) is working to identify, in the stratigraphic record, a Global Stratigraphic Section and Point (GSSP) or golden spike for a mid-twentieth century Anthropocene starting point. Rather than clarifying our understanding of the Anthropocene, we argue that the AWG’s effort to provide an authoritative definition undermines the original intent of the concept, as a call-to-arms for future sustainable management of local, regional, and global environments, and weakens the concept’s capacity to fundamentally reconfigure the established boundaries between the social and natural sciences. To sustain the creative and productive power of the Anthropocene concept, we argue that it is best understood as a “boundary object,” where it can be adaptable enough to incorporate multiple viewpoints, but robust enough to be meaningful within different disciplines. Here, we provide two examples from our work on the deep history of anthropogenic seascapes, which demonstrate the power of the Anthropocene to stimulate new thinking about the entanglement of humans and non-humans, and for building interdisciplinary solutions to modern environmental issues.
    [Show full text]
  • Dynamics of Biodiversity Change After Deforestation
    Rev. Cient. Cien. Nat. Ambien. 11(1):28-36 Gilbert • Dinámica de cambios de diversidad después Junio 2017 ISSN: 1390-8413 de deforestación Dynamics of biodiversity change after deforestation Dinámica de cambios de diversidad después de deforestación Guillermo Javier Gilbert-Jaramillo Postgraduate student. Imperial College London. London, SW7 2AZ, UK. Tel: +44(0)207589511 Recibido 5 de mayo 2017; recibido en forma revisada 26 de mayo 2017, aceptado 5 de junio 2017 Disponible en línea 26 de junio 2017 Abstract The many changes that forests have suffered over the last century have led to biodiversity loss around the planet. In order to understand these processes and try to predict future biological diversity loss, spatial comparisons have commonly been used. This research uses spatial and temporal data aiming to understand better the dynamics of these changes caused by deforestation. A meta-Analysis was conducted compiling information from 13 studies using before-after-control- impact design (BACI) to examine abundance response to deforestation. The results show clearly that biodiversity tends to decline in the five years after forest loss, though losses are not significant within the first two years. It was also found that the effects of deforestation on species abundance varied significantly among taxonomic groups, physical level species occupy in the ecosystem, type of disturbance, type of perturbation, and constancy in the surveys. The outcome of this research agrees with results of studies with spatial comparisons, though it is not yet possible to conclude which is best to predict biodiversity changes. However, these findings deepen our understanding of the complexity of biodiversity change and deforestation and emphasize importance of generating more studies that include temporal data.
    [Show full text]
  • An Essay on the Ecological and Socio-Economic Effects of the Current and Future Global Human Population Size
    An essay on the ecological and socio-economic effects of the current and future global human population size “The global human population is and will probably remain too large to allow for a sustainable use of the earth’s resources and an acceptable distribution of welfare” MSc Thesis By Jasper A.J. Eikelboom Supervised by dr. M. van Kuijk and prof. ir. N.D. van Egmond Utrecht University 27-09-2013 Abstract Since the dawn of civilization the world population has grown very slowly, but since the Industrial Revolution in 1750 and especially the Green Revolution around 1950 the growth rate increased dramatically. At the moment there are 7 billion people and in 2100 it is expected that there will be between 8.5 and 12 billion people. Currently we already overshoot the earth’s carrying capacity and this problem will become even larger in the future. Because of the global overpopulation many negative ecological and socio-economic effects occur at the moment. Land-use change, climate change, biodiversity loss, risk of epidemics, poor welfare distribution, resource scarcity and subsequent indirect effects such as factory farming and armed struggles for resources are caused by overpopulation. All these effects are long-lasting and many are irreversible. The longer we overshoot the carrying capacity of the earth and the larger the human population becomes, the worse the effects will be. It can thus be concluded that the global human population is and will probably remain too large to allow for a sustainable use of the earth’s resources and an equal distribution of the use of these resources.
    [Show full text]
  • Human Population 2018 Lecture 8 Ecological Footprint
    Human Population 2018 Lecture 8 Ecological footprint. The Daly criterea. Questions from the reading. pp. 87-107 Herman Daly “All my economists say, ‘on the one hand...on the other'. Give me a one- handed economist,” demanded a frustrated Harry S Truman. BOOKS Daly, Herman E. (1991) [1977]. Steady-State Economics (2nd. ed.). Washington, DC: Island Press. Daly, Herman E.; Cobb, John B., Jr (1994) [1989]. For the Common Good: Redirecting the Economy toward Community, the Environment, and a Sustainable Future (2nd. updated and expanded ed.). Boston: Beacon Press.. Received the Grawemeyer Award for ideas for improving World Order. Daly, Herman E. (1996). Beyond Growth: The Economics of Sustainable Development. Boston: Beacon Press. ISBN 9780807047095. Prugh, Thomas; Costanza, Robert; Daly, Herman E. (2000). The Local Politics of Global Sustainability. Washington, DC: Island Press. IS The Daly Criterea for sustainability • For a renewable resource, the sustainable rate to use can be no more than the rate of regeneration of its source. • For a non-renewable resource, the sustainable rate of use can be no greater than the rate at which a renewable resource, used sustainably, can be substituted for it. • For a pollutant, the sustainable rate of emmission can be no greater that the rate it can be recycled, absorbed or rendered harmless in its sink. http://www.footprintnetwork.org/ Ecosystem services Herbivore numbers control Carbon capture and Plant oxygen recycling and production soil replenishment Soil maintenance and processing Carbon and water storage system Do we need wild species? (negative) • We depend mostly on domesticated species for food (chickens...). • Food for domesticated species is itself from domesticated species (grains..) • Domesticated plants only need water, nutrients and light.
    [Show full text]
  • Nomadic-Colonial Life Strategies Enable Paradoxical Survival and Growth Despite Habitat Destruction Zhi Xuan Tan1, Kang Hao Cheong2*
    RESEARCH ARTICLE Nomadic-colonial life strategies enable paradoxical survival and growth despite habitat destruction Zhi Xuan Tan1, Kang Hao Cheong2* 1Yale University, New Haven, United States; 2Engineering Cluster, Singapore Institute of Technology, Singapore, Singapore Abstract Organisms often exhibit behavioral or phenotypic diversity to improve population fitness in the face of environmental variability. When each behavior or phenotype is individually maladaptive, alternating between these losing strategies can counter-intuitively result in population persistence–an outcome similar to the Parrondo’s paradox. Instead of the capital or history dependence that characterize traditional Parrondo games, most ecological models which exhibit such paradoxical behavior depend on the presence of exogenous environmental variation. Here we present a population model that exhibits Parrondo’s paradox through capital and history- dependent dynamics. Two sub-populations comprise our model: nomads, who live independently without competition or cooperation, and colonists, who engage in competition, cooperation, and long-term habitat destruction. Nomads and colonists may alternate behaviors in response to changes in the colonial habitat. Even when nomadism and colonialism individually lead to extinction, switching between these strategies at the appropriate moments can paradoxically enable both population persistence and long-term growth. Introduction *For correspondence: kanghao.cheong@singaporetech. Behavioral adaptation and phenotypic diversity are evolutionary meta-strategies that can improve edu.sg a population’s fitness in the presence of environmental variability. When behaviors or phenotypes are sufficiently distinct, a population can be understood as consisting of multiple sub-populations, Competing interests: The each following its own strategy. Counter-intuitively, even when each sub-population follows a los- authors declare that no ing strategy that will cause it to go extinct in the long-run, alternating or reallocating organisms competing interests exist.
    [Show full text]